Molecular weight tuning and spectral studies of novel CN‐PPVs via Gilch reaction route

Abstract

Two novel cyano-containing PPVs (CNPPVs) with different solubilizing alkyloxyl groups were synthesized through Gilch reaction from the monomer 2-cyano-5-(4 0 -alkoxyphenyl)-1,4-bisbromomethylbenzene. The structures of the polymers were determined by NMR, FTIR, and elemental analysis (EA). The results show that the solubility, thermal stability, and fluorescence properties of CN-PPVs vary with differing molecular weight. The relationship between the molecular weight of the polymers and the amount of 4-methoxyphenol used was consistent with anionic polymerization, of which the molecular weight is known to be inversely related to the amount of the initiator. When the number-average molecular weight (M n ) is in the range of 30,000-100,000, the solubility of the polymers was very good in chloroform, tetrahydrofuran, and toluene, and have good film properties. The fluorescence emission maxima range from 457 to 520 nm, exhibiting appreciable red-shift with the increase of the molecular weight. This series of novel CN-PPVs also bear high thermal stability.

Blue-Greenish Electroluminescent Poly(p-phenylenevinylene) Developed for Organic Light-Emitting Diode Applications

“…Here, the rather low amount of resulting material was mainly due to steric hindrance and slow reaction rates. The third step consisted of a Suzuki coupling between 2 and the corresponding boronic acid 6 , which was synthesized according to literature procedures. , Similar to the procedure described by Martin et al , compound 3 was acetylated by the addition of acetic anhydride to yield 4 before hydrolysis and nucleophilic substitution yielded monomer M 1 in 17%. Subsequent polymerization was performed under standard Gilch conditions for 3 days using an excess of base to significantly lower the amount of remaining halogen content in the polymers main chain.…”

“…5 was synthesized according to literature procedure with slight modification . 4-bromo phenol (40.0 g, 0.23 mol), dried potassium carbonate (91.0 g, 0.66 mol) and dry DMF (100 mL) were mixed under N 2 conditions and heated to 60–65 °C.…”

“…5 was synthesized according to literature procedure with slight modification. 30 4-bromo phenol (40.0 g, 0.23 mol), dried potassium carbonate (91.0 g, 0.66 mol) and dry DMF (100 mL) were mixed under N 2 conditions and heated to 60−65 °C. After 1 h 2-ethylhexyl bromide (42 mL, 0.23 mol) was added dropwise, the reaction mixture was stirred for 20 h at 60−65 °C.…”

“…6 was synthesized according to literature procedure with slight modification. 30 A solution of 5 (10.0 g, 0.035 mol) in anhydrous, degassed THF (116 mL) was cooled to −80 °C under N 2 before the addition of n-BuLi (21 mL, 0.053 mol, 2.5 M in n-hexane). The reaction mixture was stirred for 1 h at −80 °C before the addition of trimethyl borate (14 mL, 0.123 mol).…”